SUMMARY The proposed project address critical gaps in the understanding of the strength, specificity and persistence of neurobehavioral adaptions that occur in the initial period of repeated consumption of a branded sugar sweetened beverage (SSB). Half of Americans consume SSBs on any given day1. Regular SSB intake is considered a contributing factor to excess energy intake, weight gain, and obesity2?4, which impacts 70% of Americans5. A contributing factor to repeated SSB consumption is sugar intake causes to the release of dopamine (DA) and opioids in the striatum6, providing positive reinforcement. As such, multiple brain-based models of food reward-driven obesity have been proposed, largely focusing on the striatum and executive functioning7?14. These brain-based models of obesity have elucidated risk factors for overconsumption of high- sugar foods; however, data supporting these competing models rely heavily on observational studies in small samples. Importantly, previous reports from our lab and others directly implicate eating behavior patterns as a vital contributor to aberrant neurobehavioral responses to food stimuli. However, without experimental evidence, there are fundamental gaps in our knowledge about the neurobehavioral adaptations that occur as an individual begins to regularly consume a SSB prior to weight change. As observational data suggest, it is also crucial to examine individual difference factors that may exacerbate or protect against adaptations associated with regular SSB intake, as well as whether these adaptions are specific. As such, we completed a small, randomized controlled trial that assigned daily consumption of SSBs over 21 days. Results supported the hypothesis that regular SSB intake results in specified neural, behavioral, and perceptual adaptions that may increase risk for habitual consumption. To confirm and expand these preliminary data, we will randomly assign 230 young adults (18-28 years old, BMI 18-34) to consume branded versions of either flavored SSBs or unsweetened, flavored beverages daily for 3 weeks. Aim 1 will investigate specific neurobehavioral effects of repeated intake of novel SSB and logo exposure relative to unsweetened, flavored control beverages/logos, allowing for the direct test of the impact of regular high sugar beverage intake. Aim 2 will test whether individual difference factors previously implicated in obesity (e.g., overweight, SSB consumption, genetic predisposition for compromised DA functioning, Pavlovian learning) moderate the neurobehavioral response patterns as a function of daily SSB intake. This will allow us to identify exacerbating and/or protective factors of neurobehavioral adaptions as an individual begins to regularly consume a SSB. Aim 3 will examine group- and individual-level differences in extinction effects resulting from cessation of daily SSB intake, which will allow for a greater understanding of the persistence of adaptations once the beverage is removed. Collectively, these aims provide a robust examination of adaptations to regular intake of a branded SSB that promise to meaningfully advance the understanding of the maintenance and escalation of sugar intake.